Solar cells kept clean of dust and dirt with electrostatic wipe down

A new technique for electrostatically removing dirt from the surface of solar cells could remove the need to regularly wash them, potentially saving billions of litres of water every year in some of driest regions on Earth.

Solar energy is perhaps the most appealing renewable technology as it is widely scaleable. Moreover, it is readily available in arid regions that often have a pressing need for energy: clear, bright skies found in deserts maximise electricity generation. However, such regions are often dusty and this can rapidly obscure the surface of a solar cell. Dust can be removed by regularly pressure-washing the surface, but washing the solar cells accounts for up to 10% of the maintenance costs of a typical solar farm, with enough water used every year worldwide to satisfy the needs of two million people. Moreover, as the water often has to be shipped in and purified, ‘there is a CO₂ footprint associated with the water footprint too’, explains Kripa Varanasi of the Massachusetts Institute of Technology.